40 research outputs found
Analytical relationship for the cranking inertia
The wave function of a spheroidal harmonic oscillator without spin-orbit
interaction is expressed in terms of associated Laguerre and Hermite
polynomials. The pairing gap and Fermi energy are found by solving the BCS
system of two equations. Analytical relationships for the matrix elements of
inertia are obtained function of the main quantum numbers and potential
derivative. They may be used to test complex computer codes one should develop
in a realistic approach of the fission dynamics. The results given for the
Pu nucleus are compared with a hydrodynamical model. The importance of
taking into account the correction term due to the variation of the occupation
number is stressed.Comment: 12 pages, 4 figure
Liquid Drop Stability of a Superdeformed Prolate Semi-Spheroidal Atomic Cluster
Analytical relationships for the surface and curvature energies of oblate and
prolate semi-spheroidal atomic clusters have been obtained. By modifying the
cluster shape from a spheroid to a semi-spheroid the most stable shape was
changed from a sphere to a superdeformed prolate semi-spheroid (including the
flat surface of the end cap). Potential energy surfaces vs. deformation and the
number of atoms, N, illustrate this property independent of N.Comment: 5 pages, 3 figurex, revtex
Cluster Radioactivity
Cluster radioactivity (spontaneous emission of heavy particles from nuclei) is presented from a theoretical point of view in good agreement with experimental results. After a brief historical account, we give details about the analytical super asymmetric fission (ASAF) model extensively used for predicting the half-lives of heavy and superheavy (Z ≥ 104) elements. For the already measured 26 cluster decays (from 14C to 32,34Si of parent nuclides with Z = 87-96) it is clear that cluster radioactivity is a rare phenomenon in the best case about 9 orders of magnitude weaker than the competing alpha decay. Then we show the theoretical possibility of a strong cluster decay compared to alpha decay for some superheavy nuclei with Z ≥ 122, e.g. 306122; 310-314122; 306-324124, and 311-323124
Deformed two center shell model
A highly specialized two-center shell model has been developed accounting for
the splitting of a deformed parent nucleus into two ellipsoidaly deformed
fragments. The potential is based on deformed oscillator wells in direct
correspondance with the shape change of the nuclear system. For the first time
a potential responsible for the necking part between the fragments is
introduced on potential theory basis. As a direct consequence, spin-orbit {\bf
ls} and {\bf l} operators are calculated as shape dependent. Level scheme
evolution along the fission path for pairs of ellipsoidaly deformed fragments
is calculated. The Strutinsky method yields the shell corrections for different
mass asymmetries from the superheavy nucleus 122 and Cf all
along the splitting process.Comment: 32 pages, 8 figure
Alpha-decay lifetimes semiempirical relationship including shell effects
A new version of the semiempirical formula based on fission approach of alpha
decay is derived, by using the optimum values of the fitting parameters
determined for even-even nuclei, combined with hindrance factors for even-odd,
odd-even, and odd-odd nuclides. The deviations from experimental data for two
regions of nuclear chart (493 alpha emitters with Z=52-118 and 142 transuranium
nuclei including superheavies (Z=92-118), respectively) are compared with those
obtained by using the universal curve and the Viola-Seaborg semiempirical
relationship.Comment: 11 pages, 3 figures, revtex
Heavy particle radioactivities of superheavy nuclei
The concept of heavy particle radioactivity (HPR) is changed to allow emitted
particles with Z_e>28 from parents with Z>110 and daughter around 208Pb.
Calculations for superheavy (SH) nuclei with Z=104-124 are showing a trend
toward shorter half-lives and larger branching ratio relative to alpha decay
for heavier SHs. It is possible to find regions in which HPR is stronger than
alpha decay. The new mass table AME11 and the theoretical KTUY05 and FRDM95
masses are used to determine the released energy. For 124 we found isotopes
with half-lives in the range of ns to ps.Comment: 4 pages, 4 figurex, revtex4-
Synthesis of 298114 within isobaric reaction channels
Cold fusion channels are sought for the synthesis of 298114 superheavy element. The deformation energy is calculated within a multidimensional space of deformation for a two-spheroid fusion type configuration. A very complete binary macroscopic-microscopic method is used to compute the liquid drop and the shell correction terms. Static barriers are obtained by minimization over four free parameters defining the shape. The tensor of inertia is calculated with the hydrodynamical Werner–Wheeler model. Finally, the penetrability is obtained by minimizing the action integral